Crane truck



L. G. HOWLETT.

CRANE TRUCK.

APPLICATION FILED MAR.19,1919.

MIQAQE- iiifiiikif I A; 'INVENTOR BY My ATTORNEY' L. G. HOWLETT.

CRANE TRUCK,

APPLICATION FILED MAR-19, 1919.

1 ,41 2,525. atented Apr. 11, 1922.

I] 2 SHEETS-SHEET 2.

jww INVENTQR ATTORNEY UNITED STATES PATENT OFFICE.

-.:.Ew;s e. HOWLETT, or my CITY, MICHIGAN.

CRANE; rauc x.

Specification of Letters ram. t t A 11, 1922,

Application filed March 19, 1919. Serial No. 283,486.

To all whom it mafia; comer n:

Be it known that I, LEWIS G. HOWLE'IT, a citizen of the United States, residing; at Bay City, in the county of Bay and State of Michigan, have invented certain new and useful Improvements in Crane Trucks; and

I do hereby declare the following tobe a full, clear, and exact description of the invention, such as will enable others skilled 1n the art to which it appertains to make and a use the same.

This invention relates a; cranes for auto trucks and similar .vehicles and pertains more particularly to an improved means for mounting the crane on the truck frame,

whereby I am enabled to eliminate bending" moments in the truck frame caused by the leverage exerted by the load, tending to" load is suspended from the end of the boom.-

With the foregoing and certain other objects in view, which will appear later lnthe specification, my invention consists in the devices described and claimed and the equivalents thereof. V

In the drawings, Fig. 1 is a part diagram matic side view of a truck equipped with a crane embodying my improvement, the boom of the crane shown in its fore-and-aft position. I

Fig. 2 is an end position of the same with the boom swung out.

Fig. 3 is a detail of the mast and the 1ow er end of the boom.

Fig. 4 is a part sectional v1ew taken 1n a vertical plane through the head .of the mast, V. l

Fig. 5 is a similar view through the foot of themast.

Referring to Figs. land 2, 1 represents the truck frame and 2 the crane mast which is preferably of the selfesu porting-orpillar type, being made, referab y in the form of a hollow truncate cone, the baseof which is rigidly secured to'its' supporting. platform,

the base being sufiic'iently extended to firmly .which the mast 2 is supportthemast without the use 'of guy ropes or guy extension rods, from the mast to the ends of the truck frame.

3 .is a boom'so mounted on the mastvas to. be capable of being swung from the foreand-aft position of Fig. 1 to the. fore-andaft position of Fig.2. The upper end of the mast is connected to the outer end of the boom b suitable cables 4. 5 is an outrigger and ac secured to the truck frame 1 to prevent the truck platform from tipping when the load .is swung outboard, as shown in Fig, If.

6, Gare'beams comprising a sill frame, to i y S cured. This sill frame 18 also secure to the truck fr mast to a truck.

My improvement relates more particularly to this sill frame, its construction and mode ofoperation. Referring to Fig. 1, in which the boom is and e'xtendslengthwise thereof, from the point near the rear axle of the:

shown in its fore-and-aft position and assuming that the boom is loaded, it is evident I that the vertical thrust caused by the weight of the craneand its load is carried by the truck frame 1. The tendency of themastto overturn, due to the leverage of the load, Y can be counteracted in two ways-first, by

connecting the top of the mast to the front of the truck frame by guy ropes or rods;

and seoond, ;by'employ1ng a. mast of. the

self-supporting'type, asshown in the draw in I guys are employed a bending moment is Introduced in addition to the bending momentscaused by .the weight. This second bending moment acts through the guy rope in the direction indicated by the arrow at A I in Fig. 1,; tending to spring the frame 1 at a point near'the base of'the mast. When a the self-supporting mast. is employed, as

shown in Flg. 1, no guy wire is used, but -the tendencypf themast to overturn is resisted by .the base of the mast, there being a downward thrust on one side of the base and an u ward pull on the other side, as indicated y. the arrows at B, B.

I have found in practice that when the base of the crane is secured to the truck frame -1 direct that these forces B, B tend to spring the frame Sincethist'endency to spring .the frame is caused by-stresses ad- 'roo ditional to the stresses due to the weight of .the load, the capacity of the truck is considerably reduced.

I have found that this localized bending moment and tendency to buckle the frame canbe easily removed by introducing the sill frame 6 between the base of the crane and the frame 1. This sill 6 is preferably made of beams of-sufficie'nt depth to resist the bucklin tendency caused bythe forces B, B and t '0 length of the frame 6 issuificient to distribute approximately -um-' formly, in-the form of a distributed load,

indicated by the'arrows at C, and this load, whichis now in the form of a. distributed' load, instead. of a localized bending, 1110-; ment, is easilycarried by the frame '1 with-*- out tendency to buckle the frame. Conseq y" the cit of the truck for m n ha lng heavy loads is greatly ining creased. a

The mast may be made in any convenient i manner,as shown in Fig. 3, where the shell 2, preferably. madevof sheet metal, is sur- 25.

b aring 8 andsi e roller bearings 9.- Upon mounted "by; a ca 7 carrying a ball thrust .j.. these bearings-rides a revolvable head 10 carrying sheaves-1'1 and 'tie rods 12. The

" zylower ends of the tie-rods are secured to a partly encloses. the base of the mast 2 and is adapted semi-cylindrical track -13 which i to travel around the :mast when the boom is swung outwardly; To guide'the track 13,

of the load is to a great extenteliminate load with entire safety. I; Having thus described cylindrical ways14 are provided near the bottom of the mast and suitable roller bearings 15 are interposed between the track 13 andthe'ways14.-

' The boom'3iisfpivoted as atlfi to the By the means above described, I have rovided a mounting for self-supporting mast cranes, especially adapted for .use on auto trucks, whereby the bending moment in the truck frame produced by the ecoentricit in. effect converted into a substantially uniformly distributed load, thereby enabling the: truck to handle a very much hea vier my invention, what 50 I claim and desire, to secure by Letters I m a ns motor-truck chamis, a

post. crane, apair of 1ongitudinally extend- 

